How to animate a bike chain with a low poly chainring?
What you could do is create a mesh that looks like the chain, with only the necessary amount of edge loops, hook these edge loops to empties, make the ring rotate 1/7 of 360°, move the empties and keyframe them so that they follow the ring rotation. Make the empties rotate a bit on themselves so that the chain keeps an even thickness. You can now make the rotation cyclic to give the illusion that it rotates 360° and more. I haven't hooked the left part of the chain but it's the same process.